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Finding the Fourth Proportional to 285.40, 428.21 and 148.53

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Solution

The fourth proportional to 285.40, 428.21 and 148.53 is: 222.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.40 : 428.21 = 148.53 : x
  2. Step 2: Convert to fraction form
    285.40/428.21 = 148.53/x
  3. Step 3: Cross multiply
    285.40x = 428.21 × 148.53
  4. Step 4: Simplify right side
    285.40x = 63,603.87
  5. Step 5: Solve for x
    x = 63,603.87/285.40
  6. Step 6: Final answer
    x = 222.86

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.